Iris Chang always outdid Paula Kamen. When they were both journalism students in the late 80s at the University of Illinois in Urbana, it was Chang who won the prized internships. Worse, Chang had started out as a computer science major and switched with Kamen's encouragement. Long after college, Chang's drive, intelligence, and tireless research continued to put her ahead of her peers. "I was not alone in eating Iris' dust," Kamen noted ruefully in an essay she wrote for Salon shortly after Chang's death.

That essay, "How 'Iris Chang' Became a Verb," serves as a graceful and insightful eulogy for the best-selling author, who died of a self-inflicted gunshot wound on a lonely stretch of road outside San Jose, California, in November 2004. She was 36. Overwhelming response to the piece convinced Kamen to expand her meditation on Chang's phenomenal life and her shocking death. The result, Finding Iris Chang: Friendship, Ambition, and the Loss of an Extraordinary Mind, out this month from Da Capo Press, details Chang's celebrated and controversial career as a journalist and historical author as well as Kamen's relationship with her. Kamen, the author of three previous books (Feminist Fatale, on Third Wave feminism; Her Way, a study of women's sexuality in the 1990s; and All in My Head, about her years-long struggle with chronic pain), says with Chang as her subject she wanted to "focus on the dark side, the complexities and tensions we had with each other."

But Kamen's book, unlike, say, Truth & Beauty, novelist Ann Patchett's controversial memoir of her thorny friendship with the late writer Lucy Grealy, relies very little upon navel-gazing rumination. Instead it offers the same meticulous attention to detail and thorough immersion in primary sources that distinguishes Chang's exhaustively researched books, Thread of the Silkworm (1995), about an accused Chinese spy; The Rape of Nanking, published in 1997 to mark the massacre's 60th anniversary; and the 2003 narrative history The Chinese in America. During her research, Kamen uncovered secrets that the seemingly always-in-control Chang kept close until near the very end.

Kamen coined the phrase "to Iris Chang it" years before her friend's death. As a guest speaker at colleges she often cited Chang's career as an example of how to think big; she encouraged students to "just decide what you want and go get it—to the point of being naive." But while Chang was undeniably brilliant and hardworking, her undisguised ambition turned off as many people as it charmed. In her book, Kamen recalls how Chang approached an editor on one of her first days at the U. of I.'s Daily Illini and "asked simply—without small talk or polite conversation—'How do I get your job?'"

In a way Finding Iris Chang is Kamen's way of Iris Chang-ing it. As she wrote in the Salon piece, Kamen spoke to Chang by phone a few days before her death and was shocked to hear her normally upbeat friend—whose penchant for hours-long conversations could be exhausting—sound "sad and totally drained." Chang ended the conversation by asking Kamen, should anything happen to her, "to let people know what she was like before." "I got more response [from the Salon piece] than any other articles I've written combined," Kamen says. "And maybe more than the first two books I wrote combined, too."

Just what had happened to Chang was a mystery. Rumors swirled in the early days after her suicide. Some of Chang's friends blamed the relentless pace of her work. She had worn herself out on a book tour for the paperback release of The Chinese in America and spent some time in a mental health ward in Kentucky in August 2004. She was diagnosed with bipolar disorder—which Chang rejected—just two weeks before her suicide.

Others wondered if Chang's choice of subject matter was somehow to blame. In her last call to Kamen, Chang had alluded to highly placed people who didn't like her once again digging into Japanese atrocities during World War II. The Rape of Nanking, about the 1937 massacre of as many as 350,000 soldiers and civilians by Japan's imperial army, had been denounced by the Japanese ambassador to the U.S., and caricatures of Chang appeared in right-wing Japanese newspapers. (The book has yet to be translated for publication in Japan.) Chang had returned to World War II for the book she was working on when she died, interviewing survivors of the Bataan Death March who were, like the Chinese, demanding an official apology from the Japanese government.

The most startling thing Kamen uncovered about Chang, however, didn't emerge until after Finding Iris Chang was set in galleys. She'd already spoken with Chang's widower, Brett Douglas, and knew about the fertility treatments the couple had undergone in order to have their son, Christopher, who was born in 2002. (Another of Chang's unfinished projects was a book on defeating the biological clock.) Like others, Kamen had wondered if postpartum depression might have played a role in her mental decline. But Douglas finally told Kamen that Christopher had been born with the help of a surrogate mother.

After her own years of research on the interplay of hormones and the brain, Kamen believes that Chang's bipolar condition may have been exacerbated by her fertility treatments. "It seemed like a lot of odd behavior started around that time," Kamen says. Among other things, the compulsively well-organized Chang began losing credit cards every couple of weeks, according to Douglas, and in her last year she became paranoid about everything from viruses attacking her computer to attempts by the government to "recruit" her, a la The Manchurian Candidate.

Kamen says that despite her worldliness, Chang never developed the distancing filters that aid many journalists. "My friends and I would joke about the obituary assignments at a paper being 'the stiffs page.' I could never picture her having any kind of irony like that about her work."

Kamen herself says that diving into the darker reaches of Chang's life was frightening at first. "It was sort of scary as a journalist to be thinking, if this could happen to her and she supposedly had no history [of mental illness], and she was so much more put together than I am, just for me the question was how to survive our toxic topics. We need people to be covering atrocities and mental illness and genocide. But there has to be dialogue about how to do that in the long term."

In All in My Head, Kamen documents how she learned to slow down and come to terms with a life of chronic pain. Ironically, the very condition that put her career on a slower track has also helped her avoid the emotional and physical burnout that the ambitious Chang experienced during her last year. "She didn't really know a way of living or managing something where it wasn't a matter of sheer force of will."

Kamen notes that Chang applied the same careful determination to her suicide as she did to past goals. (One of the most engaging chapters in Kamen's book concerns Chang's unlikely—but successful—bid to become a homecoming princess.) She bought Derek Humphry's book on suicide, Final Exit, and sent boxes of her papers to three different archives—at the University of California at Santa Barbara, Stanford, and the U. of I.—leaving Kamen a mountain of carefully organized materials to go through. Kamen recalls once commenting on how thorough Chang's filing system was: her friend replied, "It has to be. This is for the biographers."

"Suicide," Kamen observes, "is in a lot of ways the ultimate act of control. The whole process, how she planned everything, is very, very methodical."

Kamen says Chang never understood how her drive pissed people off. "She wasn't a jealous personality. A lot of people misunderstood her in that way. She would talk about her achievements openly, and people saw her as putting them down or bragging, when it was really that she believed there was enough success to go around."

A Canadian documentary about Chang is in the works and two statues honoring her have been erected since her death—one at Stanford, the other at a memorial to the Nanking massacre in what's now called Nanjing, where another woman from Illinois is honored. Minnie Vautrin, also an alum of U. of I. in Urbana-Champaign, was a missionary and educator who saved thousands of Chinese lives during the Japanese occupation. Chang had used her diary as a source, and Vautrin's story figures prominently in her book. "When I read The Rape of Nanking, I was struck by the parallels in the lives of these two women, Minnie and Iris," Kamen writes. "And through the months afterward, I couldn't help but think of Minnie and why she captured Iris' imagination as a historian." After leaving China, Vautrin suffered a breakdown; she committed suicide in 1941.v